Ilium vs urban center

Ilium and urban center both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ilium	Yes	No	No	No
urban center	Yes	No	No	No

Ilium (noun)	urban center (noun)
an ancient city in Asia Minor that was the site of the Trojan War	a large and densely populated urban area; may include several independent administrative districts